<?php
/*
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * This software consists of voluntary contributions made by many individuals
 * and is licensed under the LGPL. For more information, see
 * <http://www.doctrine-project.org>.
 */

namespace Doctrine\Common\Cache;

/**
 * Base class for cache driver implementations.
 *
 * @since 2.0
 * @author  Benjamin Eberlei <kontakt@beberlei.de>
 * @author  Guilherme Blanco <guilhermeblanco@hotmail.com>
 * @author  Jonathan Wage <jonwage@gmail.com>
 * @author  Roman Borschel <roman@code-factory.org>
 */
abstract class AbstractCache implements Cache {
	/** @var string The cache id to store the index of cache ids under */
	private $_cacheIdsIndexId = 'doctrine_cache_ids';
	
	/** @var string The namespace to prefix all cache ids with */
	private $_namespace = null;
	
	/**
	 * Set the namespace to prefix all cache ids with.
	 *
	 * @param string $namespace
	 * @return void
	 */
	public function setNamespace($namespace) {
		$this->_namespace = $namespace;
	}
	
	/**
	 * {@inheritdoc}
	 */
	public function fetch($id) {
		return $this->_doFetch( $this->_getNamespacedId( $id ) );
	}
	
	/**
	 * {@inheritdoc}
	 */
	public function contains($id) {
		return $this->_doContains( $this->_getNamespacedId( $id ) );
	}
	
	/**
	 * {@inheritdoc}
	 */
	public function save($id, $data, $lifeTime = 0) {
		return $this->_doSave( $this->_getNamespacedId( $id ), $data, $lifeTime );
	}
	
	/**
	 * {@inheritdoc}
	 */
	public function delete($id) {
		$id = $this->_getNamespacedId( $id );
		
		if( strpos( $id, '*' ) !== false ) {
			return $this->deleteByRegex( '/' . str_replace( '*', '.*', $id ) . '/' );
		}
		
		return $this->_doDelete( $id );
	}
	
	/**
	 * Delete all cache entries.
	 *
	 * @return array $deleted  Array of the deleted cache ids
	 */
	public function deleteAll() {
		$ids = $this->getIds();
		
		foreach( $ids as $id ) {
			$this->delete( $id );
		}
		
		return $ids;
	}
	
	/**
	 * Delete cache entries where the id matches a PHP regular expressions
	 *
	 * @param string $regex
	 * @return array $deleted  Array of the deleted cache ids
	 */
	public function deleteByRegex($regex) {
		$deleted = array();
		
		$ids = $this->getIds();
		
		foreach( $ids as $id ) {
			if( preg_match( $regex, $id ) ) {
				$this->delete( $id );
				$deleted[] = $id;
			}
		}
		
		return $deleted;
	}
	
	/**
	 * Delete cache entries where the id has the passed prefix
	 *
	 * @param string $prefix
	 * @return array $deleted  Array of the deleted cache ids
	 */
	public function deleteByPrefix($prefix) {
		$deleted = array();
		
		$prefix = $this->_getNamespacedId( $prefix );
		$ids = $this->getIds();
		
		foreach( $ids as $id ) {
			if( strpos( $id, $prefix ) === 0 ) {
				$this->delete( $id );
				$deleted[] = $id;
			}
		}
		
		return $deleted;
	}
	
	/**
	 * Delete cache entries where the id has the passed suffix
	 *
	 * @param string $suffix
	 * @return array $deleted  Array of the deleted cache ids
	 */
	public function deleteBySuffix($suffix) {
		$deleted = array();
		
		$ids = $this->getIds();
		
		foreach( $ids as $id ) {
			if( substr( $id, -1 * strlen( $suffix ) ) === $suffix ) {
				$this->delete( $id );
				$deleted[] = $id;
			}
		}
		
		return $deleted;
	}
	
	/**
	 * Prefix the passed id with the configured namespace value
	 *
	 * @param string $id  The id to namespace
	 * @return string $id The namespaced id
	 */
	private function _getNamespacedId($id) {
		if( !$this->_namespace || strpos( $id, $this->_namespace ) === 0 ) {
			return $id;
		} else {
			return $this->_namespace . $id;
		}
	}
	
	/**
	 * Fetches an entry from the cache.
	 *
	 * @param string $id cache id The id of the cache entry to fetch.
	 * @return string The cached data or FALSE, if no cache entry exists for the given id.
	 */
	abstract protected function _doFetch($id);
	
	/**
	 * Test if an entry exists in the cache.
	 *
	 * @param string $id cache id The cache id of the entry to check for.
	 * @return boolean TRUE if a cache entry exists for the given cache id, FALSE otherwise.
	 */
	abstract protected function _doContains($id);
	
	/**
	 * Puts data into the cache.
	 *
	 * @param string $id The cache id.
	 * @param string $data The cache entry/data.
	 * @param int $lifeTime The lifetime. If != false, sets a specific lifetime for this cache entry (null => infinite lifeTime).
	 * @return boolean TRUE if the entry was successfully stored in the cache, FALSE otherwise.
	 */
	abstract protected function _doSave($id, $data, $lifeTime = false);
	
	/**
	 * Deletes a cache entry.
	 *
	 * @param string $id cache id
	 * @return boolean TRUE if the cache entry was successfully deleted, FALSE otherwise.
	 */
	abstract protected function _doDelete($id);
	
	/**
	 * Get an array of all the cache ids stored
	 *
	 * @return array $ids
	 */
	abstract public function getIds();
}